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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.myfaces.orchestra.requestParameterProvider.jsf;
20  
21  import javax.faces.FacesException;
22  import javax.faces.context.FacesContext;
23  import javax.faces.context.FacesContextFactory;
24  import javax.faces.lifecycle.Lifecycle;
25  import javax.servlet.http.HttpServletRequest;
26  import javax.servlet.http.HttpServletResponse;
27  
28  import org.apache.myfaces.orchestra.lib.jsf.ExternalContextUtils;
29  import org.apache.myfaces.orchestra.requestParameterProvider.RequestParameterResponseWrapper;
30  import org.apache.myfaces.orchestra.requestParameterProvider.RequestParameterServletFilter;
31  
32  /**
33   * Ensure that a custom wrapper is put around the HttpServletResponse so that encodeURL can be 
34   * intercepted and modified.
35   * <p>
36   * There is a servlet filter (RequestParameterServletFilter) that does this in the obvious way, but
37   * it is a nuisance to have to set up filters in the web.xml. This class implements a sneaky hack
38   * to get this to happen automatically for JSF applications, ie no servlet filter is needed when
39   * this is specified in the faces-config.xml file as the FacesContextFactory.
40   * <p>
41   * If you have to deal with a mixed environment e.g. JSP/JSF it would be better to use the
42   * {@link org.apache.myfaces.orchestra.requestParameterProvider.RequestParameterServletFilter}.
43   */
44  public class RequestParameterFacesContextFactory extends FacesContextFactory
45  {
46      private final FacesContextFactory original;
47  
48      public RequestParameterFacesContextFactory(FacesContextFactory original)
49      {
50          this.original = original;
51      }
52  
53      /**
54       * Invokes the getFacesContext method on the original factory in order to return a
55       * perfectly normal FacesContext instance. However the ServletResponse object passed
56       * to that FacesContext instance is a modified one that tweaks every url that is
57       * processed by the ServletResponse.encodeUrl method.
58       */
59      public FacesContext getFacesContext(Object context, Object request, Object response, Lifecycle lifecycle)
60      throws FacesException
61      {
62          if (!ExternalContextUtils.getRequestType(context, request).isPortlet())
63          {
64              HttpServletRequest httpServletRequest = (HttpServletRequest) request;
65              
66              // Wrap this request only if something else (eg a RequestParameterServletFilter)
67              // has not already wrapped it.
68              if (!Boolean.TRUE.equals(httpServletRequest.getAttribute(
69                      RequestParameterServletFilter.REQUEST_PARAM_FILTER_CALLED)))
70              {
71                  // No servlet filter has wrapped the response, so do it now for the response
72                  // referenced by this FacesContext. Note that this wrapper will therefore
73                  // apply to all output generated via the FacesContext, but not to anything
74                  // that might be written by filters etc.
75                  response = new RequestParameterResponseWrapper((HttpServletResponse) response);
76  
77                  // We now need to reassure the RequestParameterProviderManager that the response has indeed been
78                  // wrapped; it checks and reports an error if not as it is easy to stuff up this configuration.
79                  //
80                  // However we can not just set the REQUEST_PARAMETER_FILTER_CALLED flag here. If code creates its own
81                  // FacesContext instance for any reason while a request is running, then this method is called again.
82                  // On the second call this flag would already be set and the response would not be wrapped as required.
83                  //
84                  // Therefore we have two separate flags; RequestParameterProviderManager checks whether either
85                  // REQUEST_PARAM_FILTER_CALLED or REQUEST_PARAM_RESPONSE_WRAPPED has been set.
86  
87                  httpServletRequest.setAttribute(
88                      RequestParameterServletFilter.REQUEST_PARAM_RESPONSE_WRAPPED, Boolean.TRUE);
89  
90              }
91          }
92  
93          return original.getFacesContext(context, request, response, lifecycle);
94      }
95  }